Functions in a table problem

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1

Each time i click a testButton, testEnergy lowers by 2 and each time that happens i get an error “attempt to call a nil value”, thats because there are only 3 functions, on 20 energy, 10 and 0, theres no in between. Is there way to mute that error?

local testButton = GUIcameras.Test
local testEnergy = 30
local testLabel = GUIcameras.TestLabel
testButton.Text = testEnergy
local minus = 2


local testFunctions = {
	[20] = function()
		testLabel.Visible = not testLabel.Visible
		testLabel.Text = "Your energy is decent."
		
		task.wait(0.8)
		testLabel.Visible = not testLabel.Visible
	end,
	[10] = function()
		testLabel.Visible = not testLabel.Visible
		testLabel.Text = "You are getting low on energy."
		
		task.wait(0.8)
		testLabel.Visible = not testLabel.Visible
	end,
	
	[0] = function()
		testLabel.Visible = not testLabel.Visible
		testLabel.Text = "No energy!"
		minus = 0
		task.wait(0.8)
		testLabel.Visible = not testLabel.Visible
	end,
}

testButton.MouseButton1Click:Connect(function()
	testEnergy -= minus
	testButton.Text = testEnergy
	testFunctions[testEnergy]()
end)
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2 
if testFunctions[testEnergy] ~= nil then
    testFunctions[testEnergy]()
end
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3

You can check it like this
rawget function checks if a thing exists in a table (first arg) with the given index (second arg) ,if it exists then it returns the value and if it doesn’t, it returns nil

if rawget(testFunctions,testEnergy) then
rawget(testFunctions,testEnergy)()
end
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4

Hey just wondering, is my code slower than yours? I can’t check as I’m on mobile, but I’m eager to know

If you can help me, I’d like to learn more about rawget and how it compared to what I’ve done in Luau bytecode as well as speed

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5

Rawget and Rawset just bypass metamethods
Yours and his both do table lookup, except his is completely useless since the OP does not use __index metamethod

fastest is to cache it

local func = testFunctions[testEnergy]
if func then func() end

Heres a simple benchmark `1 - 1e7`
  13:06:07.731  Indexing took: 0.42579299999988507  -  Client - Client:21      NORMAL
  13:06:08.368  Rawget took: 0.6363193000001957  -  Client - Client:29         SLOWEST
  13:06:08.599  Cache took: 0.23039799999969546  -  Client - Client:41         FASTEST
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6

You are getting that error because you’re attempting to call nil, if you’re trying to accomplish calling the nearest available function that is less than or equal to energy, you can find that by doing something like:

local energyFuncs = {
	[0] = function()
		return ">= 0 energy"
	end,
	[10] = function()
		return ">= 10 energy"
	end,
	[20] = function()
		return ">= 20 energy"
	end,
	[30] = function()
		return ">= 30 energy"
	end,
}

local function getHighestEnergyFunc(energy: number)
	local highestReq, highestFunc
	for req, func in energyFuncs do
		if energy >= req and (not highestReq or req > highestReq) then
			highestReq, highestFunc = req, func
		end
	end
	
	return highestFunc
end

print(getHighestEnergyFunc(20)()) -- ">= 20 energy"

Otherwise, if you just need to call an energy function at that exact energy level, check if the function exists first before attempting to call it, by doing:

local energyFunc = energyFuncs[energy]
if energyFunc then
	energyFunc()
end
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